the sketch of the graph is misleading ...
note that , so there is a very small region between the curve and from to .
Here are some things I have done. I already found the volume since the other part of the question said to use the method of discs/washers. It is 54.0633 cubic units (correct answer).
I found by trial and error that (since this is an online assignment) that a= 9/sqrt(82) and c =9 .
What do I do? Why should there be two integrals, I don't understand.
I have tried the following.
y = 9^x becomes x = lny/ln9
Formula
h = lny/ln9
r = y
So I got integral from 9/sqrt(82) to 9 of
dy
But that's just one integral and perhaps even incorrect. Please show me what to do.
Thanks
To evaluate the volume of your region, you need to do
The only one of those integrals which may cause you any trouble is the second, so do
which you would then evaluate using integration by parts twice. See how you go
Is this the method of cylindrical shells? I am obliged to use cylindrical shells. Can you use r (radius), h(height)? And why will my answer be in the form of a sum of two integrals (see the question -top of image)?